This is a 24-week, Phase III multicenter, randomized, double-blind, double-dummy, parallel-group study. Eligible subjects will be randomized to GSK573719/GW642444 125/25mcg, GSK573719/GW642444 62.5/25mcg, GW642444 25mcg, or tiotropium treatment groups in a 1:1:1:1 ratio. Treatments will be administered once-daily in the morning by inhalation using a Novel Dry Powder Inhaler (Novel DPI) and HandiHaler. There will be a total of 9 study clinic visits conducted on an outpatient basis. Subjects who meet the eligibility criteria at Screening (Visit 1) will complete a 7 to 10 day run-in period followed by a 24-week treatment period. Clinic visits will be at Screening, Randomization (Day 1), Day 2, after 4, 8, 12, 16, and 24-weeks of treatment, and 1 day after the Week 24 Visit (also referred as Treatment Day 169). A follow-up contact for adverse assessment will be conducted by telephone approximately 7 days after Visit 9 or the Early Withdrawal Visit. The total duration of subject participation, including follow-up will be approximately 26 weeks. All subjects will be provided with albuterol/salbutamol for use on an "as-needed" basis throughout the run-in and study treatment periods. At screening, pre-bronchodilator spirometry testing will be followed by post-albuterol/salbutamol spirometry testing. Post-albuterol/salbutamol FEV1 and FEV1/forced vital capacity (FVC) values will be used to determine subject eligibility. To further characterize bronchodilator responsiveness, post-ipratropium testing will be conducted following completion of post-albuterol/salbutamol spirometry. Spirometry will be conducted at each post-randomization clinic visit. Six hour post-dose serial spirometry will be conducted at Visits 2, 6, and 8. Trough spirometry will be obtained 23 and 24 hours after the previous day's dose of blinded study medication at Visits 3 to 9. All subjects will be provided with an electronic diary (eDiary) for completion daily in the morning and the evening throughout the run-in and treatment periods. Subjects will use the eDiary to record peak expiratory flow (PEF) each morning, dyspnea scores using the Shortness of Breath with Daily Activities instrument (SOBDA), daily use of supplemental albuterol/salbutamol as either puffs/day from a metered-dose inhaler (MDI) and/or nebules used per day, and any healthcare contacts related to COPD. Additional assessments of dyspnea will be obtained using the Baseline and Transition Dyspnea Index (BDI/TDI) which is an interviewer based instrument. At Visit 2, the severity of dyspnea at baseline will be assessed using the BDI. At subsequent visits (Visits 4, 6, and 8) change from baseline will be assessed using the TDI. General health status will be evaluated using the subject-completed EQ-5D questionnaire at Visits 2, 4, 6, and 8. Disease specific health status will be evaluated using the subject-completed St. George's Respiratory Questionnaire (SGRQ) at Visits 2, 4, 6, and 8, and the subject-completed COPD Assessment Test (CAT) at Visits 2, 6, and 8. The occurrence of adverse events will be evaluated throughout the study beginning at Visit 2. SAEs will be collected over the same time period as for AEs. However, any SAEs assessed as related to study participation (e.g., study treatment, protocol-mandated procedures, invasive tests, or change in existing therapy) or related to a GSK concomitant medication, will be recorded from the time a subject consents to participate in the study up to and including any follow up contact. Additional safety assessments of vital signs (blood pressure and pulse rate), 12-lead ECGs and standard clinical laboratory tests (hematology and chemistry) will be obtained at selected clinic visits.